<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        
        var week = 2
        days = parseInt(prompt('请随意输入一个天数', 1000))
        remainingDay = days % 7
            // remainingDay = 1000 % 7   //获得1000天以后是星期一
        weekDay = 2 + remainingDay;
        if (weekDay > 7) {
            weekDay = weekDay % 7
        } else {
            weekDay
        }
        // alert("今天是星期" + weekDay);
        switch (weekDay) {
            case 1:
                alert("今天是星期一");
                break;
            case 2:
                alert("今天是星期二");
                break;
            case 3:
                alert("今天是星期三");
                break;
            case 4:
                alert("今天是星期四");
                break;
            case 5:
                alert("今天是星期五");
                break;
            case 6:
                alert("今天是星期六");
                break;
            default:
                alert("今天是星期天");
                break;
        }

    </script>
</body>
</html>